Game jerseys have been hung in equipment rooms, waiting to be dirtied once more.

Locker rooms, once full of dirty equipment and constant chatter, are empty.

Players are on vacation, spending the offseason away from the game to recharge their batteries for next season.

But behind closed doors, general managers, head coaches, scouts and other team personnel are working around the clock, searching for upgrades to their rosters.

The annual NFL Scouting Combine is set to commence this week in Indianapolis, free agency begins March 12 and the NFL Draft is on the horizon.

All of the behind-the-scenes work is well under way, and the next couple of months are critical. This is the time where teams cash in on top-of-the-line free agents and find future stars through the draft.

This is the time where teams grow or decline.

For a number of teams, this period is crucial and can’t be mismanaged. Only those who are most prepared for what lies ahead will come out on top.

Arizona Cardinals

Dilip Vishwanat/Getty ImagesArizona's Kevin Kolb drops back to pass against St. Louis on Oct. 4.

The NFC West has become one of the feistiest and most competitive divisions in the NFL. It’s a division dominated by defense and quarterbacks—two things Arizona lacks.

The Cardinals ranked No. 28 in passing last season, and a franchise quarterback is a must.

The Kevin Kolb experiment failed miserably. John Skelton is nothing more than a backup and its questionable whether Ryan Lindley belongs in the NFL.

Cardinals beat writer Kent Somers believes new head coach Bruce Arians will bring in a number of quarterbacks over the course of the offseason, according to azcentral.com.

"I think the Cardinals are going to 'flood' the quarterback position with players," Somers said, courtesy of azcentral.com. "

Arizona also needs to upgrade its offensive line, which was poor last season. This unit allowed 41 sacks through the first nine games of the season. What’s more, the Cardinals allowed a league-worst 58 sacks and the fourth-most quarterback hits, 97.

Tackle Levi Brown suffered a torn tricep in a preseason game last August, and Bobby Massie struggled in the early stages of the season but got better along the way.

Arizona was last in rushing last season, averaging 75.2 yards per game.

Kansas City Chiefs

Kansas City has enjoyed just one winning season in the last four years. Its needs are lengthy but start on offense.

Matt Cassel’s days as a Chief are all but over at this point. He’s aging, and his game has declined. Brady Quinn has yet to prove himself in the NFL and doesn’t appear to be a starter on any team.

With the No. 1 overall pick in April’s draft, it would be wise for the Chiefs to select a franchise quarterback.

However, new general manager John Dorsey told The Kansas City Starthat there isn't a quarterback in this year's draft that jumps out at him.

"There is no quarterback where personnel guys can definitely say, 'He's a first-round pick,'" Dorsey said, courtesy of The Kansas City Star.

He continued on to say,

There were so many inconsistencies in the collective group. There was not one guy that stood up and said, 'I'm the guy in the position this year.' There really wasn't one clear-cut guy.

Upgrading the offensive line is another priority for newly signed head coach Andy Reid. Guard Ryan Lilja retired last season, which leaves a void that needs to be filled.

Assuming wide receiver Dwayne Bowe seeks greener pastures, the Chiefs will also need a pair of targets for their yet-to-be-determined quarterback to throw to. They signed Mardy Gilyard, but his career has been a flop.

Jacksonville Jaguars

Blaine Gabbert has proved incapable of leading an offense. The former 2011 first-round pick started 14 games his rookie season and played most of it with a toe injury, according to NFL.com.

His second season in Jacksonville was a disaster.

Gabbert started just 10 games and threw nine touchdowns to six interceptions. His season was cut short after suffering a right forearm injury against Houston, Nov. 18.

Despite Gabbert's inconsistencies and injury history, Frank Scelfo, the Jaguars new quarterback coach, thinks highly of his young quarterback, according to The Florida Times-Union.

Though, Scelfo didn't say whether Gabbert would be the quarterback of the future. Courtesy of The Florida Times-Union,

That I can't answer, that future part. I think he's blessed with a lot of good tools physically. There's nothing he can't do on the football field. Because I haven't been able to talk football with him, we have to figure out where he is and where we've got to get him. If there are issues, then we have to overcome those.

On the defensive side of the ball, the Jaguars tallied the fewest sacks in the league last season, 20. They need a physical and aggressive defensive end and a tackle. Players that can bull their way through opposing offensive lines and get to the quarterback.

Buffalo Bills

Tom Szczerbowski/Getty ImagesBuffalo's Ryan Fitzpatrick heaves a pass against the New York Jets on Dec. 30.

Bills general manager Buddy Nix insisted on drafting a franchise quarterback in the near future, according to WGR550.com.

“Listen, we have said from Day 1, that we want to draft a good young quarterback,” Nix told WGR550.com. “I don’t want to leave here without a franchise guy for the future in place. I have not said that before, but I’m saying it now because it’s a fact.”

The Bills haven’t had a good quarterback since drafting Jim Kelly with the No. 14 overall pick of the 1983 NFL Draft. Kelly was inducted into the Hall of Fame in 2002 after a tremendous career with the Bills.

Kelly’s days have come and gone. His career is nothing more than a memory in the minds of diehard Bills fans.

The time is now for Nix to act on his words.

Buffalo also needs to add another receiver to complement Steve Johnson. Two reliable receivers are always better than one and would allow the offense to be more creative.

Cleveland Browns

Cleveland finished with a 5-11 mark last season and needs a quarterback.

Brandon Weeden will enter his second season as an NFL quarterback but turns 30 in October.

With former Carolina Panthers offensive coordinator Rob Chudzinski now calling the shots in Cleveland, Weeden’s every move will be evaluated. The Browns obviously need to think about the future in drafting a younger quarterback.

Ohio.com's Ryan Lewis said that drafting a quarterback with the No. 6 overall pick in April's draft is a "longshot," yet owner Jimmy Haslam and vice president of player personnel Mike Lombardi are skeptical of their current starter.

"Haslam said that Weeden would have competition, and Lomardi hasn't always had the most positive things to say of Weeden or how high he went in the draft," Lewis wrote, according to Ohio.com.

The Browns could also use another linebacker to boost a defense that tallied just 38 sacks last season. Jabaal Sheard led the way with seven sacks, but the Browns should find another pass rusher capable of putting heat on opposing quarterbacks for next season.

St. Louis Rams

The Rams showed tremendous improvement last season under new head coach Jeff Fisher, going 7-8-1.

Prior to that, the Rams had gone a combined 12-52 over the previous four seasons.

Fisher and general manager Les Snead successfully upgraded their roster last season through free agency and the draft but numerous voids remain.

Offensive tackle is one position the Rams could upgrade.

Rodger Saffold finished last season on a strong not after missing the majority of it because of injury. Fill-ins Barry Richardson and Wayne Hunter struggled at times, and neither appears to be a long-term solution.

Receiver is another key area for the Rams.

Danny Amendola is a great slot receiver, and rookie Chris Givens provided a deep threat for Sam Bradford. However, neither is a true No. 1 receiver. Rookie Brian Quick could become the No. 1 target, but he only caught 11 passes for 156 yards last season. The Rams need to find a big receiver either through free agency or the draft.

Last Friday, the Rams released receiver Titus Young, who they claimed off waiver from Detroit just nine days prior. According to Jim Thomas of the St. Louis Post-Dispatch, Fisher isn't worried about adding depth at the position.

"Not a concern whatsoever," Fisher said, courtesy of the Post-Dispatch. "There's options out there. The free-agent market, there's options out there, and it's a great draft for a receiver this year."

On defense, the Rams need to upgrade the safety position. Opponents consistently ran circles around Craig Dahl last season, and the odds of the five-year veteran returning are slim to none.

With the future of star running back Steven Jackson unclear, the Rams could also use another to complement last season's rookies in Daryl Richardson and Isaiah Pead.